A comprehensive review of scientific literature has uncovered no reported cases of date palm trees infected by a virus and no viral infections have been reported by farmers. In spite of the hot and humid environment t...A comprehensive review of scientific literature has uncovered no reported cases of date palm trees infected by a virus and no viral infections have been reported by farmers. In spite of the hot and humid environment they inhabit, the abundance of viral infestations in the soil, other plants and organisms surrounding the trees and the frequency of importation and transplantation of these trees into the region. Such conditions should cause the date palms to also be infected. Notably, other palm trees do not exhibit the same level of innate viral immunity that is found in date palms. The date palm tree’s innate viral immunity is a virgin area in botanical research. The biological segment in date palm tree DNA that enables survival under genotoxic radiation also deserves further investigation. This field of study may enable the breeding of other economically important plants to improve desert ecology and economy, land management, agriculture and horticulture.展开更多
Tree search is a widely used fundamental algorithm. Modern processors provide tremendous computing power by integrating multiple cores, each with a vector processing unit. This paper reviews some studies on exploiting...Tree search is a widely used fundamental algorithm. Modern processors provide tremendous computing power by integrating multiple cores, each with a vector processing unit. This paper reviews some studies on exploiting single instruction multiple date （SIMD） capacity of processors to improve the performance of tree search, and proposes several improvement methods on reported SIMD tree search algorithms. Based on blocking tree structure, blocking for memory alignment and dynamic blocking prefetch are proposed to optimize the overhead of memory access. Furthermore, as a way of non-linear loop unrolling, the search branch unwinding shows that the number of branches can exceed the data width of SIMD instructions in the SIMD search algorithm. The experiments suggest that blocking optimized SIMD tree search algorithm can achieve 1.6 times response speed faster than the un-optimized algorithm.展开更多
Because of socio-economic importance of date palm in North Africa, the scientific community has always followed the progression of parasitic disease that affects it. The study was performed on population of thirty pal...Because of socio-economic importance of date palm in North Africa, the scientific community has always followed the progression of parasitic disease that affects it. The study was performed on population of thirty palm trees belonging to three cultivars of the oases of south-west Algeria TOUAT Gourara. The analytical protocol consists of a hot hydrochloric acid hydrolysis of I g of leaf material dried and ground. Structural analysis of compounds present in extracts was conducted by chromatographic and spectrophotometric techniques. Through the analysis of all HPLC profiles of phenolic acids, we have established three chemotypes： resistant with the highest heights, sensitive, with the lowest height, finally low sensitivity or tolerant with intermediate heights. The increased synthesis of C-glycoflavones, within diseased palms, can be seen as the first sign of plant response to fungal attack, or even as a defense mechanism so these flavonoids correspond to ＂pre-inhibitines＂. It has not been found qualitative differences between different cultivars studied. The merits of our work show a negative correlation between flavonoid content and the level of lignification in the date palm, suggests that the process of lignification is more rapid in resistant cultivars. We can say that there is a constitutive resistance.展开更多
文摘A comprehensive review of scientific literature has uncovered no reported cases of date palm trees infected by a virus and no viral infections have been reported by farmers. In spite of the hot and humid environment they inhabit, the abundance of viral infestations in the soil, other plants and organisms surrounding the trees and the frequency of importation and transplantation of these trees into the region. Such conditions should cause the date palms to also be infected. Notably, other palm trees do not exhibit the same level of innate viral immunity that is found in date palms. The date palm tree’s innate viral immunity is a virgin area in botanical research. The biological segment in date palm tree DNA that enables survival under genotoxic radiation also deserves further investigation. This field of study may enable the breeding of other economically important plants to improve desert ecology and economy, land management, agriculture and horticulture.
基金Project supported by the Shanghai Leading Academic Discipline Project(Grant No.J50103)the Graduate Student Innovation Foundation of Shanghai University(Grant No.SHUCX112167)
文摘Tree search is a widely used fundamental algorithm. Modern processors provide tremendous computing power by integrating multiple cores, each with a vector processing unit. This paper reviews some studies on exploiting single instruction multiple date （SIMD） capacity of processors to improve the performance of tree search, and proposes several improvement methods on reported SIMD tree search algorithms. Based on blocking tree structure, blocking for memory alignment and dynamic blocking prefetch are proposed to optimize the overhead of memory access. Furthermore, as a way of non-linear loop unrolling, the search branch unwinding shows that the number of branches can exceed the data width of SIMD instructions in the SIMD search algorithm. The experiments suggest that blocking optimized SIMD tree search algorithm can achieve 1.6 times response speed faster than the un-optimized algorithm.
文摘Because of socio-economic importance of date palm in North Africa, the scientific community has always followed the progression of parasitic disease that affects it. The study was performed on population of thirty palm trees belonging to three cultivars of the oases of south-west Algeria TOUAT Gourara. The analytical protocol consists of a hot hydrochloric acid hydrolysis of I g of leaf material dried and ground. Structural analysis of compounds present in extracts was conducted by chromatographic and spectrophotometric techniques. Through the analysis of all HPLC profiles of phenolic acids, we have established three chemotypes： resistant with the highest heights, sensitive, with the lowest height, finally low sensitivity or tolerant with intermediate heights. The increased synthesis of C-glycoflavones, within diseased palms, can be seen as the first sign of plant response to fungal attack, or even as a defense mechanism so these flavonoids correspond to ＂pre-inhibitines＂. It has not been found qualitative differences between different cultivars studied. The merits of our work show a negative correlation between flavonoid content and the level of lignification in the date palm, suggests that the process of lignification is more rapid in resistant cultivars. We can say that there is a constitutive resistance.
